Part 2: Diving into Reta

This email might get a little wordy, but I’m going to do my best to break this down in a way that feels simple, connected and easy to understand.

My goal with this series isn't to convince you to use peptides. It's actually the opposite.

I want to take away some of the stigma surrounding them so you can understand what they are from a more neutral perspective — without automatically adopting the judgment, fear or hype we see online.

I also REALLY don't want this conversation to become part of the "unhealthy skinny" trend we're seeing everywhere right now. Let's not fall into another trap of worldly expectations telling us what our bodies are supposed to look like.

And I need to admit something before we start:

Before I started researching peptides, I had my own uneducated bias toward them.

I had formed opinions based largely on what I'd heard from other people rather than what I'd actually taken the time to learn myself.

And there may be no truer statement than:

You don't know what you don't know.

I realized I was taking other people's opinions and treating them like facts.

So I started researching.

And the more I learned, the more I realized this conversation is far more nuanced than "peptides good" or "peptides bad."

So today, let's break down one peptide you're probably going to hear A LOT about:

Retatrutide.

No white coat.

No chemistry degree.

No TikTok hype.

Just the science explained in a way that actually makes sense.

First: What IS Retatrutide?

Retatrutide is an investigational peptide-based medication being developed by Eli Lilly.

As of August 2026, retatrutide is still being studied in Phase 3 clinical trials.

Now here's where things get interesting.

Retatrutide is designed to activate three different hormone receptors:

GLP-1 GIP Glucagon

That's why you'll sometimes hear it called a:

Triple agonist.

And unless you're really into biology, you're probably thinking…

Cool. What the heck does that mean?

Let's make it make sense.

First, What Is a Peptide?

You've probably heard about medications like Ozempic and Mounjaro.

These medications work through peptide/hormone pathways too.

At the simplest level, peptides are short chains of amino acids.

And amino acids are the building blocks your body uses to make proteins.

Many naturally occurring peptides in our bodies act like messengers — carrying signals that tell different cells and systems what to do.

So rather than thinking:

"Peptide = weight-loss drug."

Think:

"Peptide = messenger."

Different peptides carry completely different messages.

And in the case of medications like semaglutide, tirzepatide and investigational retatrutide, researchers have designed molecules that interact with specific metabolic hormone receptors.

Please note: Ozempic, Mounjaro and investigational retatrutide are administered by injection in their respective clinical/approved uses.

Now let's make those three pathways really easy to understand.

Imagine Your Metabolism Is a Busy Restaurant

Think about your body like a restaurant.

Customers are coming in.

Food is arriving.

Energy is being used.

Energy is being stored.

Orders are flying everywhere.

And you've got different managers helping coordinate everything that's happening.

What's interesting about retatrutide is that instead of communicating through just one pathway, it's designed to activate three.

And each one plays a different role.

MANAGER #1: GLP-1

Think:

"We're good. We don't need another order right now."

GLP-1 is a naturally occurring hormone involved in things like:

Appetite.Satiety.Blood-glucose regulation.Digestion.

Medications that activate the GLP-1 receptor can help some people feel satisfied with less food.

And there's another term you've probably heard all over social media:

Food noise.

You know that constant conversation?

"What am I having for lunch?"

"I want something sweet."

"What's for dinner?"

"Maybe I'll have a snack."

For some people, medications targeting GLP-1 pathways can turn the volume of those thoughts down. And when someone naturally consumes fewer calories over time?

Weight may decrease.

But this is where I want to put my personal-trainer hat on for a second.

Eating less isn't automatically the same thing as eating better.

If your appetite decreases significantly, it becomes even MORE important to make sure the food you are eating is supporting your body.

Protein.

Micronutrients.

Fiber.

Hydration.

Enough overall nutrition to support your training and your life.

This is why I strongly believe anyone considering medication-assisted weight management should have qualified healthcare guidance and, where appropriate, nutrition and training support around them.

Because we're not trying to see:

How little can I possibly eat?

We're asking:

How can I properly nourish my body while working toward better health?

But retatrutide doesn't stop at GLP-1.

MANAGER #2: GIP

This is where medications like Mounjaro come into the conversation.

Mounjaro — or tirzepatide — activates both GIP and GLP-1 receptors.

GIP is another naturally occurring hormone involved in how your body responds to nutrients, including helping regulate insulin secretion after eating.

Translation?

It participates in the incredibly complicated system your body uses to manage nutrients and blood glucose after you eat.

And then we get to Manager #3.

This is where the retatrutide research becomes especially interesting.

MANAGER #3: GLUCAGON

Glucagon plays an important role in regulating the availability of stored energy.

Imagine your restaurant has a giant storage room in the back.

Glucagon is one of the signals involved in saying:

"Hey — we may need to access some of what's stored back there."

Researchers are particularly interested in combining glucagon-receptor activity with GLP-1 and GIP because of the potential effects this combination may have on energy balance and metabolism.

So rather than looking at weight management only through the lens of:

"How do we help someone consume less?"

Researchers are also studying:

"How does the body handle, store and expend energy?"

And THAT is one of the reasons retatrutide has generated so much interest.

Okay… But What Does the Research Actually Show?

I don't want to drown you in statistics.

Because sometimes I think we become so mesmerized by before-and-after photos and percentages that we forget there are actual human beings behind those numbers.

But there is one study worth understanding.

A Phase 2 clinical trial followed 338 adults with obesity, or overweight plus a weight-related condition, for 48 weeks.

At 48 weeks, the average percentage changes in body weight were approximately:

1 mg → -8.7%

4 mg → -17.1%

8 mg → -22.8%

12 mg → -24.2%

Those numbers are significant.

But please understand what they DO NOT mean.

They don't mean:

"Take 4 mg and you'll lose 17% of your body weight."

They don't mean:

"Higher dose = better."

And they certainly don't mean you should determine a dose for yourself based on a clinical-trial chart. These are averages observed across groups of people participating in a controlled clinical trial. Human bodies don't work like calculators.

Different body.

Different medical history.

Different response.

Different side effects.

Different outcome.

And there's another piece of those studies that doesn't make nearly as exciting of an Instagram Reel:

Lifestyle still mattered.

Participants in the obesity trial received counseling around nutrition and physical activity.

Which brings me back to something you're going to hear me repeat throughout this entire series:

The foundation matters more than the shot.

BUT — It's Not Just About the Scale.

And in my opinion?

It should NEVER only be about the scale.

This is another area of the research I find fascinating.

Researchers haven't only been looking at pounds lost. Retatrutide is also being investigated for its potential effects on metabolic health. For example, research involving participants with metabolic dysfunction-associated steatotic liver disease has reported substantial reductions in liver fat at higher studied doses.

Researchers have also observed changes in metabolic markers including things like blood glucose, blood pressure and blood lipids in clinical studies.

Does that mean retatrutide has been proven to prevent disease or make us live longer?

No.

And I think that's an incredibly important distinction.

Interesting research does not automatically equal a proven long-term outcome.

But it DOES give researchers more questions to investigate.

And personally, that's the part I find fascinating.

What About Muscle?

This is something I care about deeply as a trainer.

Whenever someone loses a significant amount of body weight — whether that's through calorie restriction, bariatric surgery, medication-assisted weight loss or another method — some of the weight lost can come from lean mass, not only body fat.

So I don't want our conversation to become:

"How much weight can we lose?"

I want it to become:

"How can we improve body composition while protecting strength and muscle?"

Because HELLO…

WE WANT MUSCLE.

Muscle supports strength, physical function, metabolism and healthy aging.

I don't want women terrified of taking up space.

I want women building bodies that allow them to LIVE.

Lift things.

Hike mountains.

Play with their kids.

Carry groceries.

Travel.

Move confidently.

Age independently.

Skinny should never be the ultimate goal. Strong should be.

And this is exactly why strength training and adequate nutrition matter so much during any weight-loss phase.

A medication doesn't replace those things.

And Now I Want to Give You My Opinion as a Personal Trainer.

After almost two decades working in fitness, there is one mindset around weight loss that I desperately want women to stop carrying:

"How much weight can I lose — and how fast can I lose it?"

No.

That's not the question.

The question I want you asking is:

"How can I improve my quality of life, and where does my body genuinely need support?"

Because this isn't a: "Take one shot and fix everything" conversation.

This is a WHOLE-BODY conversation.

How are you sleeping, eating, moving your body? How are your stress levels? How's your relationship with food? How's your bloodwork?

Maybe medication becomes one tool in someone's toolbox.

Maybe it doesn't.

But either way…

It shouldn't BE the toolbox.

Before You Decide — Get Honest With Yourself.

I'm going to stop this email here because I know that was A LOT.

But before we move into the next part of this series, I want you to do something that has absolutely nothing to do with clinical trials.

I want you to understand YOU.

Because before you decide whether a peptide or weight-management medication belongs anywhere in your journey, you should understand why you're considering it in the first place.

Not because Instagram told you smaller is better.

Not because someone's transformation photo made you question your own body.

Not because you're trying to become the size you were at 22.

And definitely not because you're hoping one injection will fix everything you haven't addressed elsewhere.

Grab your journal and get really honest with yourself:

1. What is being affected in my life right now because I don't feel my best in my body?

My energy? Confidence? Mobility? Sleep? Strength? Health? The way I show up for my family? My willingness to participate in things I used to love?

2. If I reached my "goal weight," what do I believe would actually change?

And more importantly:

Why does that number mean so much to me?

3. Is my goal genuinely about improving my health and quality of life — or am I chasing a body I think I'm supposed to have?

4. Where did my idea of my "ideal body" actually come from?

Me? Social media? My partner? Comparison? Diet culture?

Or a younger version of myself I'm desperately trying to become again?

5. What have I tried in the past — and why do I believe it didn't work long-term?

Was it unrealistic? Was I unsupported? Was I inconsistent? Was I doing too much at once?

Or is there something happening in my body that deserves proper medical attention?

6. Am I looking for SUPPORT — or am I looking for a shortcut?

There is absolutely nothing wrong with needing support.

But those are two very different intentions.

7. Am I willing to prioritize protecting and building muscle while losing weight?

Am I willing to strength train? Prioritize protein and overall nutrition? Recover properly?

And stop celebrating how little I managed to eat today?

8. Am I willing to change MORE than simply taking a weekly injection?

Because medication may become one tool.

But it can't be your entire toolbox.

9. What habits do I want to have in place if I eventually stop taking medication?

This one is BIG.

Because what are you actually building while you have additional support?

10. What does "healthy" actually look like for ME — outside of a clothing size or number on the scale?

11. If I lost the weight but didn't change my relationship with food, movement or myself — would I consider that success?

12. What would I want my daughter, best friend or someone I love deeply to believe about her body if she were standing in my shoes?

And am I offering myself that same compassion?

And finally…

13. If nobody else could see my body change, would I still want to do this?

Sit with that one.

Because I don't want this series to convince you to take a peptide.

And I don't want it to convince you not to take one either.

I want you educated enough to ask better questions.

I want you confident enough to advocate for your health.

And I want you grounded enough to make a decision that actually belongs to YOU.

Not TikTok.

Not diet culture.

Not the woman standing beside you at the gym.

Not someone else's before-and-after photo.

You.

Because the goal isn't to make yourself as small as possible.

The goal is to build a body and a life that allow you to LIVE as fully as possible.

Strong.

Capable.

Healthy.

Confident.

Supported.

And if you remember nothing else from this email, remember this:

The foundation matters more than the shot.

until next time, xox Lisa P.

IMPORTANT DISCLAIMER

I am a personal trainer, not a physician, pharmacist, registered dietitian or medical provider. Body Zone Fitness does not prescribe, dispense, supply or direct the dosing of retatrutide. Client experiences are individual and are not guaranteed results or proof that retatrutide caused a particular outcome. This content is for general educational and entertainment purposes only and is not medical advice or a recommendation to obtain or use any medication, peptide or supplement.